Power mechanism



J. F. SMATHERS POWER MECHANISM Filed March 10, 1924 Fig. 2. v

Patented Mar. 3, 1925.

UNITED STATES PATENT OFFICE JAMES F. SMATHERS, OF KANSAS CITY, MISSOURI, ASSIGNOR TO SMATHERS POWER 'IYPEWRITER COMPANY, OF KANSAS CITY, MISSOURI, A COMMON-LAW TRUST OF MISSOURI.

Application filed March 10, 1924. Serial No. 698,163.

To all whom it may concern:

Be it known that I. James F. SMATHERS, a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Power Mechanisms; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to power-mechanism of a kind which has been used for actuating the type-bars of a typewriting machine. In this mechanism a roller. constantly rotated by a suitable source of power. is

causedto cooperate with a cam rotatalolyv mounted on a swinging arm, the eccentricity of the cam causing the arm to swing as the cam rotates in contact with the roller.

Mechanisms of the type in question are disclosed in United States Letters Patent No. 1,077,005, dated October-28, 1913, and No. 1,227 ,846, dated May 29, 19-17, previously granted to the present applicant. In these mechanisms the cams are of solid form and of approximately elliptical outline, and they are designed to accomplish a complete operation at each half-rotation.

One object of the present invention is to improve the cams of the mechanisms in qlpestion with respect to their form, and to t is end the present cam is provided with two concave or reentrant portions between its active lobes or convex port-ions. This new form permits of a greater movement and better angle of approach to the driving roller, in a cam of a given maximum diameter.

Another object of the invention is to simplify and lighten the construction of the cam by the use of a thin stamping of sheetmetal in place of the solid metal previously used, and to this end it is proposed to construct the cam with a sheet-metal web and a marginal flange; the flange being serrated to provide a grip against the roller, and the stop-lugs being formed as integral projections from the edge of the flange.

In the accompanying drawings, Fig. 1 is a side elevation of the essential parts of a power-mechanism in which a cam embodying the present invention is used. Fig. 2 is a plan-view of a portion of the power-mechanism comprising the cam, its swinging carrier and the parts mounted in the carrier and cooperating directly with the cam. Fig. 3 is an inside elevation of one side-member of the carrier, with the escapeinent-slide mounted thereon. Fig. 4 is a side-elevation of the cam, on an enlarged scale, and Fig. 5 is a sectional view of the cam. on the line 5-5 in Fig. 4. v

The mechanism shown generally in Fig. 1 comprises a swinging carrier on which the cam is journalled, an escapement-mechanism controlling the movement of the cam and controlled by one of the keys of the typewriter, and a spring-pressed arm cooperatmg with projections on the cam to initiate its operative movements. While these parts are somewhat different in form and arrangement from those disclosed in the said patents, their operation is in general the same and will be readily understood without extended description.

As shown in Fig. 1 the power-roller 6 cooperates with a cam 7 journalled on a crosspin between the two side-plates of a cam-carrier 8, and the carrier is pivoted, at one end, to the frame of the machine by means of a cross-pin 9. The other end of the carrier is connected, through a link 10 and a lever 11 with one of the type-bars 12 of the machine.

The escapement-mechanism comprises two detents, 13 and 14, projecting from a. slide 15, which is mounted slidably on the inner side of one of the side-plates, and this slide is also provided with a pin 16. This pin is engaged by the slotted end of an arm 17 depending from the key-lever 27. The detents cooperate with stop-lugs26 on the cam, these lugs being so located as to arrest movement of the cam in one or the other of its idle positions.

The cam carries two projections 18 which cooperate with an arm 19 pivoted between the side-plates of the cam-carrier. A spring 20 causes this arm to press constantly against the projections 18, and the latter are so located that this pressure has a tendency, when the cam is released by the escapement-mechanism, to cause a partial rotation by which the cam is thrown into engage ment with the power-roller.

The present invention relates particularly to the form and construction of the cam and its appendages. As shown, the body of the cam is made of a single piece of sheet-metal, which is drawn into cupped form so as to provide a. web 21 and a marginal flange 22. The hub of the cam is a separate bushing 23 fixed to the web. The outline of the cam is such that it has two convex lobes 2%, between which are interposed two concave or reentrant portions 25. The parts 24 are serrated to give a better grip against the surface of the roller (5, and their forward or operative flanks are preferably so formed as to give an approximately uniform rise.

The cam is shown in its normal idle position, in Fig. 1, and it will be evident that in this position the concave portion 25 provides ample clearance between the cam and the roller. At the same time, however, only a slight relative motion is necessary to engage the active part 24 of the cam with the roller, so that the action of the mechanism is quickly responsive to the control of the key.

The sheet-metal construction of the cam not only permits it to be made at low cost and of light weight, but it particularly facilitates the provision of the stop-lugs 26, for these lugs have the form as shown, of integral projections from the edge of the flange 22. The thin web 21 also affords convenience in the use of short and light studs constituting the projections 18.

Certain features of the mechanism herein illustrated and described, particularly the unitary assembly of the cam and its controlling members upon the cam-carrier 8, are not claimed herein, as a part of the presentinvention, since they have already been disclosed and claimed in my co-pending application Serial N 0. 563,208, filed May 24th, 1922.

The invention claimed is 1. In a pmver-mechanism of the kind described, a cam formed integrally of sheetmetal and comprising a web, a serrated flange at the margin of the web, and a stoplug projecting integrally from the edge of the flange.

2. In a power-mechanism of the kind described, a cam comprising two convex lobes and two intermediate reentrant portions, and stop-lugs for arresting movement of the cam with one or the other of the reentrant portions presented to the-driving-roller of the mechanism.

3. In a power-mechanism of the kind described, a cam formed integrally of sheetmetal and comprising a web and a serrated flange; stop-lugs projecting from the edge of the flange; projections extending in the opposite direction from the web; and ahubbushing fixed at the middle of the web.

JAMES F. SMATHERS. 

